Field of the Invention
The present disclosure relates to a driving circuit, and more particularly to a driving circuit with adjustable termination resistor.
Description of the Related Art
During the recent years, the mobile personal electronic devices become more popular. The wide use of the smart phones, digital cameras, notebooks and other consumer products increases a demand for memory having low power consumption and long storage time. The demand for non-volatile memory is increased accordingly. The major feature of the non-volatile memory is that the content stored by the non-volatile memory would not disappear even under the power failure situation. Similar to a hard drive, the non-volatile memory is can be used as a reliable storage device.
The resistive memory is made of a transistor and a memory element (that is, the 1T1R type), wherein the resistance of the memory element can be changed by applied voltage or applied current. The structure of the memory element is a metal-insulator-metal (MIM) element, and the MIM element can be made by materials of perovskite oxides and transition metal oxides. The resistance of the insulator can be changed by applying different voltages to the insulator having the feature of variable resistance, so as to write data in the memory element or erase the memory element. Different resistances of the memory element indicate different data. When reading data stored in the memory element, a small bias voltage is applied and reads the current passing through the memory element to determine the logic data stored therein.
When the operation speed of the electronic devices becomes faster, frequency of interface signal between the memory device and the controller is increased to reduce the latency during signal transmission. Therefore, the signal transmission is affected by external noise more easily and a reflected signal may be generated and transmitted back to the memory device, which may cause failure of accessing the memory device. To avoid the effect caused by the reflected signal, the termination resistor is applied to absorb the reflected signal to reduce possible signal interference or noise.
Moreover, the bus transmission interface used with the personal computer or electronic device has a high transmission speed. An example of the bus transmission interface includes a universal serial bus (USB), a PCI Express (PCIe) interface, and a serial advanced technology attachment (SATA) bus. Thus, in a high-speed transceiver, the termination resistor is used for the impedance match on the transmission line to avoid the signal distortion and return loss caused by the impedance mismatch.